Plasma generating device, substrate processing apparatus, and method of manufacturing semiconductor device

ABSTRACT

There is provided a substrate processing apparatus that includes a substrate support configured to support one or more substrates, a process chamber in which the one or more substrates are processed, a gas supplier configured to supply gas, and a plasma generator including a plurality of first rod-shaped electrodes connected to a high-frequency power supply; and a second rod-shaped electrode installed between two first rod-shaped electrodes is grounded; and a buffer structure configured to accommodate the plurality of first rod-shaped electrodes and the second rod-shaped electrode, and having a first wall surface on which a gas supply port that supplies gas into the process chamber is installed. Wherein the plasma generator is configured to convert gas into plasma by the plurality of first rod-shaped electrodes and the second rod-shaped electrode to supply the plasma-converted gas to the process chamber from the gas supply port.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a Continuation Application of U.S. application Ser.No. 16/250,673 filed on Jan. 17, 2019 which is a Bypass ContinuationApplication of PCT International Application No. PCT/JP2017/012414,filed Mar. 27, 2017, the disclosure of which is incorporated herein inits entirety by reference.

TECHNICAL FIELD

The present disclosure relates to a plasma generating device, asubstrate processing apparatus, and a method of manufacturing asemiconductor device.

BACKGROUND

As one of the semiconductor device manufacturing processes, there may beperformed substrate processing in which a substrate is loaded into aprocess chamber of a substrate processing apparatus, a precursor gas anda reaction gas supplied into the process chamber are activated usingplasma, and various films such as an insulating film, a semiconductorfilm, a conductor film and the like are formed on the substrate orremoved from the substrate. Plasma is used to promote a reaction of adeposited thin film, to remove impurities from a thin film, or to assista chemical reaction of a film-forming precursor.

However, along with a progressive miniaturization in the manufacture ofa semiconductor device, it is required to perform substrate processingat a lower temperature. Therefore, in order to uniformly process apredetermined film to be processed, a solution such as increasinghigh-frequency power serving as a plasma source or the like has beenconsidered. However, if the high-frequency power is increased, it may bedifficult to uniformly process a predetermined film.

The present disclosure provides some embodiments of a technique capableof uniformly processing a substrate.

SUMMARY

According to one embodiment of the present disclosure, there is provideda technique that includes: at least one first electrode connected to ahigh-frequency power supply; and at least one second electrode to begrounded, wherein the first electrode and the second electrode arealternately arranged such that a number of electrodes of the firstelectrode and the second electrode are in an odd number of three or morein total, and the second electrode is used in common for two of thefirst electrode being respectively adjacent to the second electrode usedin common.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a schematic configuration diagram of a vertical processfurnace of a substrate processing apparatus suitably used in anembodiment of the present disclosure, in which the process furnace isshown in a vertical sectional view.

FIG. 2 is a schematic configuration diagram of a vertical processfurnace of a substrate processing apparatus suitably used in anembodiment of the present disclosure, in which the process furnace isshown in a sectional view taken along line A-A in FIG. 1.

FIG. 3A is an enlarged horizontal sectional view for explaining a bufferstructure of a substrate processing apparatus suitably used in anembodiment of the present disclosure, and FIG. 3B is a schematic viewfor explaining a buffer structure of a substrate processing apparatussuitably used in an embodiment of the present disclosure.

FIG. 4 is a schematic configuration diagram of a controller of asubstrate processing apparatus suitably used in an embodiment of thepresent disclosure, in which a control system of the controller is shownin a block diagram.

FIG. 5 is a flowchart of a substrate processing process according to anembodiment of the present disclosure.

FIG. 6 is a diagram showing the gas supply timing in a substrateprocessing process according to an embodiment of the present disclosure.

FIG. 7 is a schematic horizontal sectional view for explainingmodification 1 of the vertical process furnace of the substrateprocessing apparatus suitably used in the embodiment of the presentdisclosure.

FIG. 8 is a schematic horizontal sectional view for explainingmodification 2 of the vertical process furnace of the substrateprocessing apparatus suitably used in the embodiment of the presentdisclosure.

FIG. 9 is a schematic horizontal sectional view for explainingmodification 3 of the vertical process furnace of the substrateprocessing apparatus suitably used in the embodiment of the presentdisclosure.

FIG. 10 is a schematic configuration diagram of a vertical processfurnace of a substrate processing apparatus suitably used in anotherembodiment of the present disclosure, in which the process furnace isshown in a vertical sectional view.

FIG. 11 is a diagram showing the gas supply timing in a substrateprocessing process according to another embodiment of the presentdisclosure.

DETAILED DESCRIPTION Embodiment of the Present Disclosure

Hereinafter, an embodiment of the present disclosure will be describedwith reference to FIGS. 1 to 6.

(1) Configuration of Substrate Processing Apparatus (Heating Device)

As shown in FIG. 1, a process furnace 202 is a so-called vertical typefurnace capable of accommodating substrates in multiple stages in avertical direction and includes a heater 207 as a heating device(heating mechanism). The heater 207 has a cylindrical shape and isvertically installed by being supported by a heater base (not shown) asa holding plate. The heater 207 also functions as an activationmechanism (excitation part) that thermally activates (excites) a gas aswill be described later.

(Process Chamber)

Inside the heater 207, a reaction tube 203 is arranged concentricallywith the heater 207. The reaction tube 203 is made of a heat-resistantmaterial such as, for example, quartz (SiO₂), silicon carbide (SiC),silicon nitride (SiN) or the like and is formed in a cylindrical shapewith its upper end closed and its lower end opened. Under the reactiontube 203, a manifold (inlet flange) 209 is disposed concentrically withthe reaction tube 203. The manifold 209 is made of a metal such as, forexample, stainless steel (SUS) or the like and is formed in acylindrical shape with its upper and lower ends opened. The upper endportion of the manifold 209 is engaged with the lower end portion of thereaction tube 203 and is configured to support the reaction tube 203. AnO ring 220 a as a seal member is installed between the manifold 209 andthe reaction tube 203. As the manifold 209 is supported by the heaterbase, the reaction tube 203 is vertically installed. A process container(reaction container) is mainly formed of the reaction tube 203 and themanifold 209. A process chamber 201 is formed in the hollow portionwhich is the inside of the process container. The process chamber 201 isconfigured to be able to accommodate a plurality of wafers 200 assubstrates. The process container is not limited to the aboveconfiguration. Only the reaction tube 203 may be referred to as aprocess container in some cases.

In the process chamber 201, nozzles 249 a and 249 b are provided so asto penetrate a side wall of the manifold 209. Gas supply pipes 232 a and232 b are connected to the nozzles 249 a and 249 b, respectively. Asdescribed above, the reaction tube 203 is provided with two nozzles 249a and 249 b and two gas supply pipes 232 a and 232 b so that pluralkinds of gases can be supplied into the process chamber 201.

Mass flow controllers (MFC) 241 a and 241 b as flow rate controllers(flow rate control parts) and valves 243 a and 243 b as on-off valvesare installed in the gas supply pipes 232 a and 232 b sequentially fromthe upstream side of a gas flow. Gas supply pipes 232 c and 232 d forsupplying an inert gas are connected to the gas supply pipes 232 a and232 b, respectively, on the downstream side of the valves 243 a and 243b. MFCs 241 c and 241 d and valves 243 c and 243 d are respectivelyinstalled in the gas supply pipes 232 c and 232 d sequentially from theupstream side of a gas flow.

As shown in FIG. 2, the nozzle 249 a is installed in the space betweenan inner wall of the reaction tube 203 and wafers 200 so as to extendupward in a stacking direction of wafers 200 from a lower portion of theinner wall of the reaction tube 203 to an upper portion thereof. Inother words, the nozzle 249 a is installed along a wafer arrangementregion in a region horizontally surrounding the wafer arrangement regionon the lateral side of the wafer arrangement region (mounting region)where the wafers 200 are arranged (mounted). That is, the nozzle 249 ais installed in a direction perpendicular to the surfaces (flatsurfaces) of the wafers 200 on the lateral side of the end portions(peripheral edge portions) of the respective wafers 200 loaded into theprocess chamber 201. Gas supply holes 250 a for supplying a gas areformed on the side surface of the nozzle 249 a. The gas supply holes 250a are opened so as to face the center of the reaction tube 203 and arecapable of supplying a gas toward the wafers 200. The gas supply holes250 a are formed from the lower portion of the reaction tube 203 to theupper portion thereof. The respective gas supply holes 250 a have thesame opening area and are formed at the same opening pitch.

A nozzle 249 b is connected to a tip of the gas supply pipe 232 b. Thenozzle 249 b is installed in a buffer chamber 237 which is a gasdispersion space. As shown in FIG. 2, the buffer chamber 237 isinstalled along the stacking direction of the wafers 200 in an annularspace between the inner wall of the reaction tube 203 and the wafers 200in a plan view and in a region extending from a lower portion of theinner wall of the reaction tube 203 to the upper portion thereof. Inother words, the buffer chamber 237 is formed by a buffer structure 300so as to extend along the wafer arrangement region in a regionhorizontally surrounding the wafer arrangement region on the lateralside of the wafer arrangement region. The buffer structure 300 is madeof insulating material such as quartz or the like. Gas supply ports 302and 304 for supplying a gas are formed on the arc-shaped wall surface ofthe buffer structure 300. As shown in FIGS. 2 and 3, the gas supplyports 302 and 304 are disposed at positions facing plasma generationregions 224 a and 224 b between rod-shaped electrodes 269 and 270 andbetween the rod-shaped electrodes 270 and 271 as described below and areopened so as to face the center of the reaction tube 203, so that a gascan be supplied toward the wafers 200. A plurality of the gas supplyports 302 and 304 are formed from the lower portion of the reaction tube203 to the upper portion thereof. The respective gas supply ports 302and 304 have the same opening area and are formed at the same openingpitch.

The nozzle 249 b is installed so as to extend upward in the stackingdirection of the wafers 200 from the lower portion of the inner wall ofthe reaction tube 203 to the upper portion thereof. In other words, thenozzle 249 b is installed inside the buffer structure 300, i.e., in aregion horizontally surrounding the wafer arrangement region on thelateral side of the wafer arrangement region where the wafers 200 arearranged, so as to extend along the wafer arrangement region. That is,the nozzle 249 b is installed in the direction perpendicular to thesurfaces of the wafers 200 on the lateral side of the end portions ofthe wafers 200 loaded into the process chamber 201. Gas supply holes 250b for supplying a gas are formed on the side surface of the nozzle 249b. The gas supply holes 250 b are opened so as to face the wall surfaceformed in a radial direction with respect to the arc-shaped wall surfaceof the buffer structure 300. The gas supply holes 250 b can supply a gastoward the wall surface. As a result, the reaction gas is dispersed inthe buffer chamber 237 and is not directly blown onto the rod-shapedelectrodes 269 to 271, thereby suppressing generation of particles. Aswith the gas supply holes 250 a, a plurality of the gas supply holes 250b are formed from the lower portion of the reaction tube 203 to theupper portion thereof.

As described above, in the present embodiment, the gas is fed via thenozzles 249 a and 249 b and the buffer chamber 237 arranged in avertically-elongated space having an annular plan-view shape, i.e., acylindrical space defined by the inner wall of the side wall of thereaction tube 203 and end portions of a plurality of the wafers 200arranged in the reaction tube 203. The gas is initially injected intothe reaction tube 203 in the vicinity of the wafers 200 from the nozzles249 a and 249 b and the gas supply holes 250 a and 250 b and the gassupply ports 302 and 304 which are respectively opened in the bufferchamber 237. The main flow of the gas in the reaction tube 203 is movedin a direction parallel to the surfaces of the wafers 200, i.e., in thehorizontal direction. With such a configuration, it is possible touniformly supply the gas to the respective wafers 200, and it ispossible to improve uniformity of film thicknesses of the films formedon the respective wafers 200. The gas flowing on the surfaces of thewafers 200, i.e., the residual gas remaining after the reaction flowstoward the exhaust port, i.e., toward an exhaust pipe 231 to bedescribed later. However, the flow direction of the residual gas isappropriately specified depending on the position of the exhaust portand is not limited to the vertical direction.

From the gas supply pipe 232 a, a precursor containing a predeterminedelement, for example, a silane precursor gas containing silicon (Si) asa predetermined element is supplied into the process chamber 201 via theMFC 241 a, the valve 243 a and the nozzle 249 a.

The precursor gas is a precursor in a gaseous state, for example, a gasobtained by vaporizing a precursor kept in a liquid state under a roomtemperature and an atmospheric pressure, or a precursor kept in agaseous state under the room temperature and the atmospheric pressure.In the subject specification, when the term “precursor” is used, it maymean a “liquid precursor in a liquid state”, a “precursor gas in agaseous state”, or both.

As the silane precursor gas, it may be possible to use, for example, aprecursor gas containing Si and a halogen element, i.e., a halosilaneprecursor gas. The halosilane precursor is a silane precursor having ahalogen group. The halogen element contains at least one elementselected from a group consisting of chlorine (Cl), fluorine (F), bromine(Br) and iodine (I). That is, the halosilane precursor contains at leastone halogen group selected from a group consisting of a chloro group, afluoro group, a bromo group and an iodo group. The halosilane precursormay be said to be a kind of halide.

As the halosilane precursor gas, it may be possible to use, for example,a precursor gas containing Si and Cl, i.e., a chlorosilane precursorgas. As the chlorosilane precursor gas, it may be possible to use, forexample, a dichlorosilane (SiH₂Cl₂, abbreviation: DCS) gas.

From the gas supply pipe 232 b, a reactant containing an elementdifferent from the above-mentioned predetermined element, for example, anitrogen (N)-containing gas as a reaction gas is supplied into theprocess chamber 201 via the MFC 241 b, the valve 243 b and the nozzle249 b. As the N-containing gas, it may be possible to use, for example,a hydrogen-nitride-based gas. The hydrogen-nitride-based gas may also bea material composed of only two elements, N and H, and acts as anitriding gas, i.e., an N source. As the hydrogen-nitride-based gas, itmay be possible to use, for example, an ammonia (NH₃) gas.

From the gas supply pipes 232 c and 232 d, an inert gas, for example, anitrogen (N₂) gas is supplied into the process chamber 201 via the MFCs241 c and 241 d, the valves 243 c and 243 d, the gas supply pipes 232 aand 232 b, and the nozzles 249 a and 249 b.

A precursor supply system as a first gas supply system is mainlyconstituted by the gas supply pipe 232 a, the MFC 241 a and the valve243 a. A reactant supply system as a second gas supply system is mainlyconstituted by the gas supply pipe 232 b, the MFC 241 b and the valve243 b. An inert gas supply system is mainly constituted by the gassupply pipes 232 c and 232 d, the MFCs 241 c and 241 d, and the valves243 c and 243 d. The precursor supply system, the reactant supply systemand the inert gas supply system are collectively and simply referred toas a gas supply system (gas supply part).

(Plasma Generation Part)

As shown in FIGS. 2 and 3, three rod-shaped electrodes 269, 270 and 271made of a conductive material and having an elongated structure arearranged in the buffer chamber 237 and are arranged to extend from thelower portion of the reaction tube 203 to the upper portion thereofalong the stacking direction of the wafers 200. Each of the rod-shapedelectrodes 269, 270 and 271 is installed in parallel to the nozzle 249b. Each of the rod-shaped electrodes 269, 270 and 271 is protected bybeing covered with an electrode protection tubetube 275 from the upperportion to the lower portion thereof. The rod-shaped electrodes 269 and271 disposed at both ends among the rod-shaped electrodes 269, 270 and271 are connected to a high-frequency power supply 273 via a matcher272, and the rod-shaped electrode 270 is grounded by being connected toa ground which is a reference potential. That is, the rod-shapedelectrodes, which are connected to the high-frequency power supply 273,and the rod-shaped electrode to be grounded are alternately disposed.The rod-shaped electrode 270 disposed between the rod-shaped electrodes269 and 271 connected to the high-frequency power supply 273 is agrounded rod-shaped electrode and is used in common with respect to theelectrodes 269 and 271. In other words, the grounded rod-shapedelectrode 270 is disposed so as to be sandwiched between the rod-shapedelectrodes 269 and 271 connected to the adjacent high-frequency powersupply 273. The rod-shaped electrode 269 and the rod-shaped electrode270, and the rod-shaped electrode 271 and the rod-shaped electrode 270,are respectively configured to form a pair, thereby generating plasma.That is, the grounded rod-shaped electrode 270 is used in common for thetwo rod-shaped electrodes 269 and 271 disposed adjacent to therod-shaped electrode 270 and connected to the high-frequency powersupply 273. By applying high-frequency (RF) power to the rod electrodes269 and 271 from the high-frequency power supply 273, plasma isgenerated in the plasma generation region 224 a between the rod-shapedelectrodes 269 and 270 and in the plasma generation region 224 b betweenthe rod-shaped electrodes 270 and 271. A plasma generating part (plasmagenerating device) as a plasma source is mainly constituted by therod-shaped electrodes 269, 270 and 271 and the electrode protection tube275. The matcher 272 and the high-frequency power supply 273 may beincluded in the plasma source. As will be described later, the plasmasource functions as a plasma excitation part (activation mechanism) forplasma-exciting a gas, i.e., for exciting (activating) a gas into aplasma state.

The electrode protection tube 275 has a structure capable of beinginserted into the buffer chamber 237 in a state in which each of the rodelectrodes 269, 270 and 271 is isolated from the atmosphere in thebuffer chamber 237. If an O₂ concentration in the electrode protectiontube 275 is about the same as an O₂ concentration in the external air(atmosphere), the rod-shaped electrodes 269, 270 and 271 respectivelyinserted into the electrode protection tube 275 may be oxidized by theheat generated from the heater 207. Therefore, an inert gas such as anN₂ gas or the like is filled in the electrode protection tube 275, orthe inside of the electrode protection tube 275 is purged with an inertgas such as an N₂ gas or the like by using an inert gas purge mechanism.This makes it possible to reduce the O₂ concentration in the electrodeprotection tube 275 and to prevent oxidation of the rod-shapedelectrodes 269, 270 and 271.

(Exhaust Part)

An exhaust pipe 231 for exhausting the atmosphere in the process chamber201 is installed in the reaction tube 203. A vacuum pump 246 as a vacuumevacuation device is connected to the exhaust pipe 231 via a pressuresensor 245 as a pressure detector (pressure detection part) fordetecting the pressure in the process chamber 201 and an APC (AutoPressure Controller) valve 244 as an exhaust valve (pressure regulationpart). The APC valve 244 is a valve configured so that the vacuumevacuation of the interior of the process chamber 201 and the stop ofthe vacuum evacuation can be performed by opening and closing the valvein a state in which the vacuum pump 246 is operated, and so that thepressure in the process chamber 201 can be regulated by adjusting thevalve opening degree based on the pressure information detected by thepressure sensor 245 in a state in which the vacuum pump 246 is operated.An exhaust system is mainly constituted by the exhaust pipe 231, the APCvalve 244 and the pressure sensor 245. The vacuum pump 246 may beincluded in the exhaust system. The exhaust pipe 231 is not limited tobeing installed in the reaction tube 203 and may be installed in themanifold 209 just like the nozzles 249 a and 249 b.

A seal cap 219 as a furnace opening lid capable of airtightly closingthe lower end opening of the manifold 209 is installed below themanifold 209. The seal cap 219 is configured to make contact with thelower end of the manifold 209 from the lower side in the verticaldirection. The seal cap 219 is made of a metal such as, for example, SUSor the like and is formed in a disc shape. On an upper surface of theseal cap 219, there is installed an O ring 220 b as a seal member whichmakes contact with the lower end of the manifold 209. On the side of theseal cap 219 opposite to the process chamber 201, there is installed arotation mechanism 267 for rotating a boat 217 to be described later. Arotating shaft 255 of the rotating mechanism 267 passes through the sealcap 219 and is connected to the boat 217. The rotation mechanism 267 isconfigured to rotate the wafers 200 by rotating the boat 217. The sealcap 219 is configured to be raised and lowered in the vertical directionby a boat elevator 115 as an elevating mechanism vertically installedoutside the reaction tube 203. The boat elevator 115 is configured toload and unload the boat 217 into and from the process chamber 201 byraising and lowering the seal cap 219. The boat elevator 115 isconfigured as a transfer device (transfer mechanism) for transferringthe boat 217, i.e., the wafers 200 into and from the process chamber201. Furthermore, under the manifold 209, there is installed a shutter219 s as a furnace opening lid capable of airtightly closing the lowerend opening of the manifold 209 while lowering the seal cap 219 by theboat elevator 115. The shutter 219 s is made of a metal such as, forexample, SUS or the like and is formed in a disk shape. On the uppersurface of the shutter 219 s, there is installed an O-ring 220 c as aseal member which makes contact with the lower end of the manifold 209.The opening/closing operations (the elevating operation, the rotatingoperation and the like) of the shutter 219 s are controlled by a shutteropening/closing mechanism 115 s.

(Substrate Support Tool)

As shown in FIG. 1, the boat 217 as a substrate support tool isconfigured so as to support a plurality of wafers 200, for example, 25to 200 wafers 200 at multiple stages in a horizontal posture and in avertically-aligned state with their centers aligned with one another,namely so as to arrange the wafers 200 at predetermined intervals. Theboat 217 is made of a heat-resistant material such as, for example,quartz or SiC. Heat insulating plates 218 made of a heat-resistantmaterial such as, for example, quartz or SiC are disposed at multiplestages in the lower portion of the boat 217.

As shown in FIG. 2, in the reaction tube 203, there is installed atemperature sensor 263 as a temperature detector. By adjusting acondition of electrical conduction to the heater 207 based on thetemperature information detected by the temperature sensor 263, thetemperature inside the process chamber 201 is controlled to have adesired temperature distribution. The temperature sensor 263 isinstalled along the inner wall of the reaction tube 203 just like thenozzles 249 a and 249 b.

(Control Device)

Next, the control device will be described with reference to FIG. 4. Asshown in FIG. 4, the controller 121 as a control part (control device)is configured as a computer including a CPU (Central Processing Unit)121 a, a RAM (Random Access Memory) 121 b, a memory device 121 c and anI/O port 121 d. The RAM 121 b, the memory device 121 c and the I/O port121 d are configured to exchange data with the CPU 121 a via an internalbus 121 e. An input/output device 122 formed of, for example, a touchpanel or the like is connected to the controller 121.

The memory device 121 c is configured by, for example, a flash memory, ahard disc drive (HDD), or the like. A control program for controllingthe operations of the substrate processing apparatus, a process recipein which sequences and conditions of a film-forming process to bedescribed later are written, and the like are readably stored in thememory device 121 c. The process recipe functions as a program forcausing the controller 121 to execute each sequence in various processes(film-forming process), which will be described later, to obtain apredetermined result. Hereinafter, the process recipe and the controlprogram will be generally and simply referred to as a “program.”Further, the process recipe is simply referred to as a “recipe.” Whenthe term “program” is used herein, it may indicate a case of includingonly the recipe, a case of including only the control program, or a caseof including both the recipe and the control program. The RAM 121 b isconfigured as a memory area (work area) in which a program or data readby the CPU 121 a is temporarily stored.

The I/O port 121 d is connected to the MFCs 241 a to 241 d, the valves243 a to 243 d, the pressure sensor 245, the APC valve 244, the vacuumpump 246, the heater 207, the temperature sensor 263, the matcher 272,the high-frequency power supply 273, the rotation mechanism 267, theboat elevator 115, the shutter opening/closing mechanism 115 s, and thelike.

The CPU 121 a is configured to read the control program from the memorydevice 121 c and execute the same. The CPU 121 a is also configured toread the process recipe from the memory device 121 c according to aninput of an operation command from the input/output device 122. The CPU121 a is configured to control, according to the contents of the processrecipe thus read, the operation of the rotation mechanism 267, the flowrate adjustment operation of various gases by the MFCs 241 a to 241 d,the opening/closing operation of the valves 243 a to 243 d, theadjustment operation of the high-frequency power supply 273 based onimpedance monitoring, the opening/closing operation of the APC valve244, the pressure regulation operation performed by the APC valve 244based on the pressure sensor 245, the driving and stopping of the vacuumpump 246, the temperature adjustment operation performed by the heater207 based on the temperature sensor 263, the adjustment operation of theforward and reverse rotation, the rotation angle and rotation speed ofthe boat 217 by the rotation mechanism 267, the operation of raising andlowering the boat 217 with the boat elevator 115, and the like.

The controller 121 may be configured by installing, in a computer, theabove-described program stored in an external memory device (e.g., amagnetic disk such as a hard disk or the like, an optical disk such as aCD or the like, a magneto-optical disk such as an MO or the like, or asemiconductor memory such as a USB memory or the like) 123. The memorydevice 121 c or the external memory device 123 is configured as acomputer-readable recording medium. Hereinafter, the memory device 121 cand the external memory device 123 will be generally and simply referredto as a “recording medium.” When the term “recording medium” is usedherein, it may indicate a case of including only the memory device 121c, a case of including only the external memory device 123, or a case ofincluding both the memory device 121 c and the external memory device123. The provision of the program to the computer may be performed byusing a communication means such as the Internet or a dedicated linewithout using the external memory device 123.

(2) Substrate Processing Process

Next, a process of forming a thin film on a wafer 200 using thesubstrate processing apparatus 100 will be described as a semiconductordevice manufacturing process with reference to FIGS. 5 and 6. In thefollowing description, the operations of the respective partsconstituting the substrate processing apparatus are controlled by thecontroller 121.

Description will now be made on an example where a silicon nitride film(SiN film) as a film containing Si and N is formed on a wafer 200 byperforming a step of supplying a DCS gas as a precursor gas and a stepof supplying a plasma-excited NH₃ gas as a reaction gas, a predeterminednumber of times (one or more times), in a non-simultaneous manner, i.e.,without synchronization. Moreover, for example, a predetermined film maybe formed in advance on the wafer 200. In addition, a predeterminedpattern may be formed in advance on the wafer 200 or the predeterminedfilm.

In this specification, the process flow of the film-forming processshown in FIG. 6 may be denoted as follows for the sake of convenience.Similar notations are also used in the following modifications and otherembodiments.

(DCS→NH₃*)×n⇒SiN

When the term “wafer” is used herein, it may refer to a wafer itself ora laminated body of a wafer and a predetermined layer or film formed onthe surface of the wafer. Furthermore, when the phrase “a surface of awafer” is used herein, it may refer to a surface of a wafer itself or asurface of a predetermined layer or the like formed on a wafer.Moreover, the expression “a predetermined layer is formed on a wafer” asused herein may mean that a predetermined layer is directly formed on asurface of a wafer itself or that a predetermined layer is formed on alayer or the like formed on a wafer. In addition, when the term“substrate” is used herein, it may be synonymous with the term “wafer.”

(Loading Step: S1)

When a plurality of wafers 200 is charged on the boat 217 (wafercharging), the shutter 219 s is moved by the shutter opening/closingmechanism 115 s to open the lower end opening of the manifold 209(shutter open). Thereafter, as shown in FIG. 1, the boat 217 supportingthe plurality of wafers 200 is lifted up by the boat elevator 115 and isloaded into the process chamber 201 (boat loading). In this state, theseal cap 219 seals the lower end of the manifold 209 through the O-ring220 b.

(Pressure Regulation/Temperature Adjustment Step: S2)

The interior of the process chamber 201, namely the space in which thewafers 200 exist, is vacuum-evacuated (pressure-reducing exhaust) by thevacuum pump 246 so as to reach a desired pressure (degree of vacuum). Atthis time, the pressure in the process chamber 201 is measured by thepressure sensor 245. The APC valve 244 is feedback-controlled based onthe measured pressure information. The vacuum pump 246 is kept operatedat least until the film-forming step described later is completed.

Further, the wafer 200 in the process chamber 201 is heated by theheater 207 so as to have a desired temperature. At this time, thecondition of conductance to the heater 207 is feedback-controlled basedon the temperature information detected by the temperature sensor 263 sothat the inside of the process chamber 201 has a desired temperaturedistribution. The heating of the inside of the process chamber 201 bythe heater 207 is continuously performed at least until the film-formingstep to be described later is completed. However, in the case where thefilm-forming step is performed under a temperature condition of roomtemperature or lower, the heating of the inside of the process chamber201 by the heater 207 may not be performed. When only the processing atsuch a temperature is performed, the heater 207 is unnecessary and theheater 207 may not be installed in the substrate processing apparatus.In this case, it is possible to simplify a configuration of thesubstrate processing apparatus.

Subsequently, the rotation of the boat 217 and the wafer 200 by therotation mechanism 267 is started. The rotation of the boat 217 and thewafer 200 by the rotation mechanism 267 is continuously performed atleast until the film-forming step is completed.

(Film-Forming Step: S3, S4, S5 and S6)

Thereafter, a film-forming step is performed by sequentially executingsteps S3, S4, S5 and S6.

(Precursor Gas Supply Step: S3 and S4)

In step S3, a DCS gas is supplied to the wafer 200 in the processchamber 201.

The valve 243 a is opened, and the DCS gas is allowed to flow into thegas supply pipe 232 a. A flow rate of the DCS gas is adjusted by the MFC241 a. The DCS gas is supplied from the gas supply holes 250 a into theprocess chamber 201 via the nozzle 249 a and is exhausted from theexhaust pipe 231. At the same time, the valve 243 c is opened to allowan N₂ gas to flow into the gas supply pipe 232 c. A flow rate of the N₂gas is adjusted by the MFC 241 c. The N₂ gas is supplied into theprocess chamber 201 together with the DCS gas and is exhausted from theexhaust pipe 231.

In order to suppress an intrusion of the DCS gas into the nozzle 249 b,the valve 243 d is opened to allow an N₂ gas to flow into the gas supplypipe 232 d. The N₂ gas is supplied into the process chamber 201 via thegas supply pipe 232 b and the nozzle 249 b and is exhausted from theexhaust pipe 231.

A supply flow rate of the DCS gas controlled by the MFC 241 a is set toa flow rate falling within a range of, for example, 1 sccm or more and6000 sccm or less, preferably 2000 sccm or more and 3000 sccm or less. Asupply flow rate of the N₂ gas controlled by the MFCs 241 c and 241 d isset to a flow rate falling within a range of, for example, 100 sccm ormore and 10000 sccm or less. A pressure in the process chamber 201 isset to a pressure falling within a range of, for example, 1 Pa or moreand 2666 Pa or less, preferably 665 Pa or more and 1333 Pa or less. Atime for exposing the wafer 200 to the DCS gas is set to a time fallingwithin a range of, for example, 1 second or more and 10 seconds or less,preferably 1 second or more and 3 seconds or less.

A temperature of the heater 207 is set so that a temperature of thewafer 200 becomes a temperature falling within a range of, for example,0 degrees C. or more and 700 degrees C. or less, preferably a roomtemperature (25 degrees C.) or more and 550 degrees C. or less, morepreferably 40 degrees C. or more and 500 degrees C. or less. By settingthe temperature of the wafer 200 to 700 degrees C. or less, specifically550 degrees C. or less, or more specifically 500 degrees C. or less asin the present embodiment, it is possible to reduce an amount of heatapplied to the wafer 200 and to satisfactorily control a thermal historyundergone by the wafer 200.

By supplying the DCS gas to the wafer 200 under the above-mentionedconditions, a Si-containing layer having a thickness of, for example,from less than one atomic layer (one molecular layer) to several atomiclayers (several molecular layers) is formed on the wafer 200 (a basefilm on its surface). The Si-containing layer may be a Si layer, may bea DCS adsorption layer or may include both.

As referred to herein, a layer having a thickness of less than oneatomic layer (one molecular layer) means an atomic layer (molecularlayer) formed discontinuously, and a layer having a thickness of oneatomic layer (one molecular layer) means an atomic layer (molecularlayer) formed continuously. The Si-containing layer may include both theSi layer and the DCS adsorption layer. However, as described above, theexpression “one atomic layer”, “several atomic layers” or the like isused for the Si-containing layer. The “atomic layer” is usedsynonymously with the “molecular layer.”

When the thickness of the Si-containing layer formed on the wafer 200exceeds several atomic layers, a modifying action in a modifying processdescribed later does not reach the entire Si-containing layer.Furthermore, a minimum value of the thickness of the Si-containing layerthat can be formed on the wafer 200 is less than one atomic layer.Therefore, it is preferable that the thickness of the Si-containinglayer is from less than one atomic layer to several atomic layers.

After the Si-containing layer is formed, the valve 243 a is closed, andthe supply of the DCS gas into the process chamber 201 is stopped. Atthis time, the APC valve 244 is kept opened, the inside of the processchamber 201 is vacuum-evacuated by the vacuum pump 246, and the DCS gasunreacted or contributed to the formation of the Si-containing layer,the reaction byproduct and the like, which remain in the process chamber201, are removed from the process chamber 201 (S4). Furthermore, thevalves 243 c and 243 d are kept opened, and the supply of the N₂ gasinto the process chamber 201 is maintained. The N₂ gas acts as a purgegas. This step S4 may be omitted.

As the precursor gas, in addition to the DCS gas, it may be possible tosuitably use: various aminosilane precursor gases such as atetrakisdimethylaminosilane (Si[N(CH₃)₂]₄, abbreviation: 4DMAS) gas, atrisdimethylaminosilane (Si[N(CH₃)₂]₃H, abbreviation: 3DMAS) gas, abisdimethylaminosilane (Si[N(CH₃)₂]₂H₂, abbreviation: BDMAS) gas, abisdiethylaminosilane (Si[N(C₂H₅)₂]₂H₂, abbreviation: BDEAS) gas, abis-tertiary-butyl aminosilane (SiH₂[NH(C₄H₉)]₂, abbreviation: BTBAS)gas, a dimethylaminosilane (DMAS) gas, a diethylaminosilane (DEAS) gas,a dipropylaminosilane (DPAS) gas, a diisopropylaminosilane (DIPAS) gas,a butylaminosilane (BAS) gas, a hexamethyldisilazane (HMDS) gas and thelike; inorganic halosilane precursor gases such as a monochlorosilane(SiH₃Cl, abbreviation: MCS) gas, a trichlorosilane (SiHCl₃,abbreviation: TCS) gas, a tetrachlorosilane (SiCl₄, abbreviation: STC)gas, a hexachlorodisilane (Si₂Cl₆, abbreviation: HCDS) gas, anoctachlorotrisilane (Si₃Cl₈, abbreviation: OCTS) gas and the like; andhalogen-group-free inorganic silane precursor gases such as a monosilane(SiH₄, abbreviation: MS) gas, a disilane (Si₂H₆, abbreviation: DS) gas,a trisilane (Si₃H₈, Abbreviation: TS) gas and the like.

As the inert gas, in addition to the N₂ gas, it may be possible to use arare gas such as an Ar gas, a He gas, an Ne gas, a Xe gas or the like.

(Reaction Gas Supply Step: S5 and S6)

After the film-forming process is finished, a plasma-excited NH₃ gas asa reaction gas is supplied to the wafer 200 in the process chamber 201(S5).

In this step, opening and closing control of the valves 243 b to 243 dis performed in the same procedure as opening and closing control of thevalves 243 a, 243 c and 243 d in step S3. A flow rate of the NH₃ gas isadjusted by the MFC 241 b. The NH₃ gas is supplied into the bufferchamber 237 via the nozzle 249 b. At this time, high-frequency power issupplied between the rod-shaped electrodes 269, 270 and 271. The NH₃ gassupplied into the buffer chamber 237 is excited into a plasma state(activated into plasma). The excited the NH₃ gas is supplied into theprocess chamber 201 as active species (NH₃*) and is exhausted from theexhaust pipe 231.

A supply flow rate of the NH₃ gas controlled by the MFC 241 b is set toa flow rate falling within a range of, for example, 100 sccm or more and10000 sccm or less, preferably 1000 sccm or more and 2000 sccm or less.The high-frequency power applied to the rod-shaped electrodes 269, 270and 271 is set to electric power falling within a range of, for example,50 W or more and 600 W or less. The pressure in the process chamber 201is set to a pressure falling within a range of, for example, 1 Pa ormore and 500 Pa or less. By using plasma, it is possible to activate theNH₃ gas even if the pressure in the process chamber 201 is set to fallwithin such a relatively low pressure band. A time during which theactive species obtained by exciting the NH₃ gas with plasma is suppliedto the wafer 200, i.e., the gas supply time (irradiation time) is set toa time falling within a range of, for example, 1 second or more and 180seconds or less, preferably 1 second or more and 60 seconds or less.Other processing conditions are the same processing conditions as thoseof S3 described above.

By supplying the NH₃ gas to the wafer 200 under the above-mentionedconditions, the Si-containing layer formed on the wafer 200 isplasma-nitrided. At this time, the Si—Cl bond and the Si—H bond of theSi-containing layer are broken by an energy of the plasma-excited NH₃gas. Cl and H whose bonds with Si are broken are desorbed from theSi-containing layer. Then, Si in the Si-containing layer which has adangling bond due to desorption of Cl or the like is bonded to Ncontained in the NH₃ gas, thereby forming a Si—N bond. As the reactiongoes forward, the Si-containing layer is changed (modified) to a layercontaining Si and N, i.e., a silicon nitride layer (SiN layer).

In order to modify the Si-containing layer into the SiN layer, the NH₃gas needs to be plasma-excited and supplied. This is because, even ifthe NH₃ gas is supplied in a non-plasma atmosphere, an energy necessaryfor nitriding the Si-containing layer is insufficient in theaforementioned temperature range. This makes it difficult tosufficiently desorb Cl or H from the Si-containing layer or tosufficiently nitride the Si-containing layer to increase Si—N bonds.

After changing the Si-containing layer to an SiN layer, the valve 243 bis closed and the supply of the NH₃ gas is stopped. Furthermore, supplyof the high-frequency power to the rod-shaped electrodes 269, 270 and271 is stopped. Then, the NH₃ gas and the reaction byproducts remainingin the process chamber 201 are eliminated from the inside of the processchamber 201 (S6) by the same processing procedure and processingconditions as those of step S4. This step S6 may be omitted.

As the nitriding agent, i.e., the NH₃-containing gas to beplasma-excited, in addition to the NH₃ gas, it may be possible to use adiazene (N₂H₂) gas, a hydrazine (N₂H₄) gas, an N₃H₈ gas or the like.

As the inert gas, in addition to the N₂ gas, it may be possible to use,for example, various rare gases exemplified in step S4.

(Performed a Predetermined Number of Times: S7)

By performing, a predetermined number of times (n times), i.e., one ormore times, a cycle in which the aforementioned steps S3, S4, S5 and S6are performed in a non-simultaneous manner, i.e., withoutsynchronization, in the named order (S 7), it is possible to form a SiNfilm having a predetermined composition and a predetermined filmthickness on the wafer 200. The aforementioned cycle is preferablyrepeated a plurality of times. That is, the thickness of the SiN layerformed per cycle is set smaller than a desired film thickness, and theaforementioned cycle is preferably repeated a plurality of times untilthe film thickness of the SiN film formed by stacking the SiN layerbecomes the desired film thickness.

(Atmospheric Pressure Restoration Step: S8)

When the above-described film-forming process is completed, an N₂ gas asan inert gas is supplied into the process chamber 201 from each of thegas supply pipes 232 c and 232 d, and is exhausted from the exhaust pipe231. As a result, the interior of the process chamber 201 is purged withthe inert gas, and the gas or the like remaining in the process chamber201 is removed from the inside of the process chamber 201 (inert gaspurge). Thereafter, the atmosphere in the process chamber 201 isreplaced with the inert gas (inert gas replacement), and the pressure inthe process chamber 201 is restored to the atmospheric pressure (S8).

(Unloading Step: S9)

Thereafter, the seal cap 219 is lowered by the boat elevator 115, thelower end of the manifold 209 is opened, and the processed wafers 200are unloaded from the lower end of the manifold 209 to the outside ofthe reaction tube 203 while being supported by the boat 217 (boatunloading) (S9). After the boat unloading, the shutter 219 s is moved,and the lower end opening of the manifold 209 is sealed by the shutter219 s via the O ring 220 c (shutter closing). After the processed wafers200 are unloaded to the outside of the reaction tube 203, they are takenout from the boat 217 (wafer discharging). After the wafer discharging,an empty boat 217 may be loaded into the process chamber 201.

(3) Effects of the Present Embodiment

According to the present embodiment, one or more of the followingeffects may be obtained.

(a) According to the present embodiment, by using a plurality ofelectrodes, it is possible to increase an electrode area and to increasegeneration amount of active species to be supplied to a wafer surface,thereby increasing the amount of active species supplied to the wafersurface.(b) According to the present embodiment, by using a plurality ofelectrodes, it is possible to reduce an output, thus suppressing thegeneration of particles.(c) According to the present embodiment, by setting the number ofelectrodes to an odd number and allowing the electrode on the groundside to be shared by the electrodes on the high-frequency power supplyside, it is possible to reduce an installation space as compared with acase where even number of electrodes are used.(d) According to the present embodiment, by installing three electrodesin the buffer chamber, it is possible to form two plasma generationregions. By forming the gas supply ports at the positions (between theelectrodes) corresponding to the plasma generation regions, it ispossible to increase the supply amount of active species to be suppliedto the wafer surface. As a result, it becomes possible to form a film ina short time and to improve the throughput.(e) By installing the plasma generation part in the buffer chamber, itis possible to supply some active species even to an outside of thebuffer chamber, thereby improving an in-plane uniformity of the wafer.

(Modification 1)

Next, a modification of the present embodiment will be described withreference to FIG. 7. In this modification, only the portions differentfrom those of the above-described embodiment will be described below,and the same portions will not be described.

In the above-described embodiment, there has been specifically describedthe configuration in which the buffer structure 300 is installed on theinner wall of the reaction tube 203 and the rod-shaped electrodes 269,270 and 271 respectively covered with the electrode protection tubes 275and the nozzle 249 b are installed inside the buffer structure 300. Inthis modification, however, a buffer structure 400 having the sameconfiguration as the buffer structure 300 is further installed on theinner wall of the reaction tube 203.

On the inner side of the buffer structure 400, rod-shaped electrodes369, 370 and 371 respectively covered with electrode protection tubes275 and a nozzle 249 c are installed. The rod-shaped electrodes 369 and371 disposed at both ends among the rod-shaped electrodes 369, 370 and371 are connected to a high-frequency power supply 373 via a matcher372, and the rod-shaped electrode 370 is grounded by being connected tothe ground which is a reference potential. The nozzle 249 c is connectedto the gas supply pipe 232 b and can supply the same gas as the nozzle249 b. On the side surface of the nozzle 249 c, a plurality of gassupply holes 250 c for supplying a gas is formed from the lower portionto the upper portion of the reaction tube 203. The gas supply holes 250c are opened so as to face the wall surface extending in a radialdirection with respect to the wall surface of the buffer structure 400formed in a circular arc shape. The gas supply holes 250 c can supplythe gas toward the wall surface. Gas supply ports 402 and 404 forsupplying the gas in the buffer chamber 237 are formed on the arc-shapedwall surface of the buffer structure 400. The gas supply ports 402 and404 are opened so as to face the center of the reaction tube 203respectively at positions facing plasma generation regions 324 a and 324b between the rod-shaped electrodes 369 and 370 and between therod-shaped electrodes 370 and 371. A plurality of the gas supply ports402 and 404 are formed from the lower portion to the upper portion ofthe reaction tube 203. The respective gas supply ports 402 and 404 havethe same opening area and are formed at the same opening pitch.

The buffer structure 300 and the buffer structure 400 are installed,with the exhaust pipe 231 interposed therebetween, in a line-symmetricalmanner with respect to a line passing through the exhaust pipe 231 and acenter of the reaction tube 203. Furthermore, the nozzle 249 a isinstalled at a position facing the exhaust pipe 231 across the wafers200. In addition, the nozzle 249 b and the nozzle 249 c are installed atpositions distant from the exhaust pipe 231 in the buffer chamber 237.

In this modification, two buffer structures each having a plasmageneration part are installed. The respective buffer structures 300 and400 are provided with high-frequency power supplies 273 and 373 andmatchers 272 and 372, respectively. The respective high-frequency powersupplies 273 and 373 are connected to the controller 121 so that plasmacontrol can be performed for each of the buffer chambers 237 of thebuffer structures 300 and 400. That is, the controller 121 monitorsimpedances of the respective plasma generation parts and independentlycontrols the respective high-frequency power supplies 273 and 373 so asto prevent occurrence of a bias in the active species amount for eachbuffer chamber 237. When the impedance is large, the electric power ofthe high-frequency power supplies is controlled to become high. As aresult, a sufficient amount of active species can be supplied to thewafer even if the high-frequency power of each plasma generation part isreduced as compared with a case of using only one plasma generationpart, and the in-plane uniformity of the wafer. Furthermore, instead ofperforming plasma control for two plasma generation parts by onehigh-frequency power supply, the high-frequency power supply isinstalled for each plasma generation part. Therefore, it is possible toeasily grasp an abnormality such as disconnection or the like occurringin each plasma generation part. Moreover, it is easy to adjust thedistance between the high-frequency power supply and each electrode.Therefore, it is possible to easily suppress the difference in RF powerapplication caused by the difference in distance between each electrodeand the high-frequency power supply.

(Modification 2)

Next, modification 2 of the present embodiment will be described withreference to FIG. 8. In modification 2, three buffer structures eachhaving a plasma generation part are installed on the inner wall of thereaction tube 203, and two nozzles for supplying a precursor gas areinstalled.

As in the buffer structures 300 and 400, rod-shaped electrodes 469, 470and 471 covered with electrode protection tubes 275 and a nozzle 249 dare installed inside a buffer structure 500. The rod-shaped electrodes469 and 471 are connected to a high-frequency power supply via a matcher(not shown), and the rod-shaped electrode 470 is grounded by beingconnected to the ground which is a reference potential. The nozzle 249 dis connected to the gas supply pipe 232 b and can supply the same gas asthe gas supplied through the nozzle 249 b. Gas supply ports 502 and 504for supplying a gas are installed between the electrodes on thearc-shaped wall surface of the buffer structure 500. The gas supplyports 502 and 504 are opened so as to face the center of the reactiontube 203 respectively at the positions facing the plasma generationregions between the rod-shaped electrodes 469 and 470 and between therod-shaped electrodes 470 and 471. A plurality of the gas supply ports502 and 504 are formed from the lower portion to the upper portion ofthe reaction tube 203. The respective gas supply ports 502 and 504 havethe same opening area and are formed at the same opening pitch. Inaddition, the nozzle 249 e is connected to the gas supply pipe 232 a andcan supply the same gas as the gas supplied through the nozzle 249 a.

The buffer structure 300 and the buffer structure 400 are installed,with the exhaust pipe 231 interposed therebetween, in a line-symmetricalmanner with respect to a line passing through the exhaust pipe 231 andthe center of the reaction tube 203. Furthermore, the buffer structure500 is installed at a position facing the exhaust pipe 231 with thewafer 200 interposed therebetween. The nozzles 249 a and 249 e forsupplying a precursor gas are installed between the buffer structure 300and the buffer structure 500 and between the buffer structure 400 andthe buffer structure 500, respectively. The nozzles 249 b, 249 c and 249d for supplying a reaction gas are respectively disposed on the sameside in the buffer chamber 237. The gas supply holes of the nozzles 249b, 249 c and 249 d are opened so as to face the wall surface extendingin the radial direction with respect to the arc-shaped wall surface ofeach of the buffer structures 300, 400 and 500.

According to modification 2, effects similar to those of theabove-described embodiment and modification 1 may be obtained.

(Modification 3)

Next, modification 3 of the present embodiment will be described withreference to FIG. 9. In modification 3, four buffer structures eachhaving a plasma generation part are installed on the inner wall of thereaction tube 203.

As in the buffer structures 300, 400 and 500, rod-shaped electrodes 569,570 and 571 respectively covered with electrode protection tubes 275 anda nozzle 249 f are installed in the buffer structure 600. The rod-shapedelectrodes 569 and 571 are connected to a high-frequency power supplyvia a matcher (not shown), and the rod-shaped electrode 570 is groundedby being connected to the ground which is a reference potential. Thenozzle 249 f is connected to the gas supply pipe 232 b and can supplythe same gas as the gas supplied through the nozzle 249 b. Gas supplyports 602 and 604 for supplying a gas are installed between theelectrodes on the arc-shaped wall surface of the buffer structure 600.The gas supply ports 602 and 604 are opened so as to face the center ofthe reaction tube 203 respectively at the positions facing the plasmageneration regions between the rod-shaped electrodes 569 and 570 andbetween the rod-shaped electrodes 570 and 571. A plurality of the gassupply ports 602 and 604 are formed from the lower portion to the upperportion of the reaction tube 203. The respective gas supply ports 602and 604 have the same opening area and are formed at the same openingpitch.

The buffer structures 300, 400, 500 and 600 are installed at regularintervals. The nozzle 249 a is installed at a position facing theexhaust pipe 231 with the wafer 200 interposed therebetween. The nozzle249 b and the nozzle 249 c are respectively installed on the sidefarther from the exhaust pipe 231 in the buffer chamber 237. The nozzle249 d and the nozzle 249 f are installed on the exhaust pipe 231 side inthe buffer chamber 237. The gas supply holes of the nozzle 249 b, thenozzle 249 c, the nozzle 249 d and the nozzle 249 f are opened so as toface the wall surface extending in the radial direction with respect tothe arc-shaped wall surface of each of the buffer structures 300, 400,500 and 600.

According to modification 3, effects similar to those of theabove-described embodiment and modification 1 may be obtained.

Another Embodiment of the Present Disclosure

Next, another embodiment of the present disclosure will be describedwith reference to FIGS. 10 and 11. In this embodiment, only the partsdifferent from the above-described embodiment will be described below,and the same parts will not be described.

In the present embodiment, a gas supply pipe 232 e for supplying amodifying gas is connected to the gas supply pipe 232 b on thedownstream side of the valve 243 b. On the gas supply pipe 232 e, an MFC241 e and a valve 243 e are installed sequentially from the upstreamside of a gas flow. A gas supply pipe 232 f for supplying an inert gasis connected to the gas supply pipe 232 e on the downstream side of thevalve 243 e. On the gas supply pipe 232 f, an MFC 241 f and a valve 243f are installed sequentially from the upstream side of a gas flow.

From the gas supply pipe 232 e, a modifying gas, for example, a hydrogen(H₂) gas is supplied into the process chamber 201 via the MFC 241 e, thevalve 243 e, the gas supply pipe 232 b and the nozzle 249 b. From thegas supply pipe 232 f, an inert gas, for example, a nitrogen (N₂) gas issupplied into the process chamber 201 via the MFC 241 f, the valve 243f, the gas supply pipe 232 b and the nozzle 249 b.

Then, as shown in FIG. 11, a silicon nitride film (SiN film) as a filmcontaining Si and N is formed on the wafer 200 by performing a step ofsupplying a DCS gas as a precursor gas, a step of supplying aplasma-excited NH₃ gas as a reaction gas and a step of supplying aplasma-excited H₂ gas as a modifying gas, a predetermined number oftimes (one or more times), in a non-simultaneous manner, i.e., withoutsynchronization.

(DCS→NH₃*→H₂*)×n⇒SiN

As described above, the present disclosure may also be applied to a casewhere an NH₃ gas as a reaction gas is plasma-excited and supplied fromthe nozzle 249 b to the wafer and then an H₂ gas is plasma-excited andsupplied to the wafer. In this case, effects similar to those of theabove-described embodiment may be obtained. Furthermore, the presentdisclosure may also be applied to a case where there is a plurality ofbuffer structures, such as the case where there are two bufferstructures as in modification 1 or the case where there three bufferstructures as in modification 2. In this case, effects similar to thoseof the above-described embodiment and modifications may be obtained.

The embodiments of the present disclosure have been concretely describedabove. However, the present disclosure is not limited to theabove-described embodiments, and various modifications may be madewithout departing from the spirit thereof.

For example, in the above-described embodiments, there has beendescribed the example where three electrodes are used as the plasmageneration part. However, the present disclosure is not limited to thisexample. The present disclosure is also applicable to a case of usingthree or more odd number of electrodes such as five electrodes or sevenelectrodes. For example, in the case of forming a plasma generation partusing five electrodes, it may be possible to adopt a configuration inwhich three electrodes in total including two electrodes arranged at theoutermost positions and one electrode arranged at the center positionare connected to a high-frequency power supply and two electrodesarranged in such a form as to be sandwiched by a high-frequency powersupply is grounded.

Furthermore, in the above-described embodiments, there has beendescribed the example where the number of electrodes on thehigh-frequency power supply side is larger than the number of electrodeson the ground side, and the electrode on the ground side is made commonto the electrodes on the high-frequency power supply side. However, thepresent disclosure is not limited to this example. The number ofelectrodes on the ground side may be made larger than the number ofelectrodes on the high-frequency power supply side, and the electrode onthe high-frequency power supply side may be made common to theelectrodes on the ground side. However, when the number of electrodes onthe ground side is made larger than the number of electrodes on thehigh-frequency power supply side, it is necessary to increase theelectric power applied to the electrodes on the high-frequency powersupply side. Thus, many particles may be generated. Therefore, it ispreferable that the number of electrodes on the high-frequency powersupply side is set to be larger than the number of electrodes on theground side.

Furthermore, in the above-described embodiments, there has beendescribed the example where the gas supply ports 302 and 304 formed inthe buffer structure have the same opening area and are installed at thesame opening pitch. However, the present disclosure is not limited tothis example. The opening area of the gas supply ports 302 may be largerthan the opening area of the gas supply ports 304. As the number ofelectrodes in the buffer chamber 237 increases, there is a highpossibility that the plasma generated between the rod-shaped electrodes269 and 270 located at the positions distant from the nozzle 249 bbecomes smaller than the plasma generated between the rod-shapedelectrodes 270 and 271 located at the positions close to the nozzle 249b. Therefore, the opening area of the gas supply ports 302 formed at thepositions distant from the nozzle 249 b may be made larger than theopening area of the gas supply ports 304 formed at the positions closeto the nozzle 249 b.

Furthermore, in the above-described embodiments, there has beendescribed the configuration in which, when installing a plurality ofbuffer structures, the same reaction gas is excited by plasma andsupplied to the wafer. However, the present disclosure is not limited tothis configuration. For each buffer structure, different reaction gasesmay be plasma-excited and supplied to the wafer. This makes it possibleto control plasma for each buffer chamber and to supply differentreaction gases for each buffer chamber. As compared with a case whereplural types of reaction gases are supplied by one buffer structure, itis possible to reduce the number of unnecessary steps such as a purgestep or the like and to improve the throughput.

In the above-described embodiments, there has been described the examplewhere the reaction gas is supplied after supplying the precursor. Thepresent disclosure is not limited to such an example. The supply orderof the precursor and the reaction gas may be reversed. That is, theprecursor may be supplied after supplying the reaction gas. By changingthe supply order, it becomes possible to change the film quality and thecomposition ratio of the film to be formed.

In the above-described embodiments, there has been described the examplewhere the SiN film is formed on the wafer 200. The present disclosure isnot limited to such an example and may also be suitably applied to acase where an Si-based oxide film such as a silicon oxide film (SiOfilm), a silicon oxycarbide film (SiOC film), a silicon oxycarbonitridefilm (SiOCN film), a silicon oxynitride film (SiON film) or the like isformed on the wafer 200, or a case where a Si-based nitride film such asa silicon carbonitride film (SiCN film), a silicon boronitride film(SiBN film), a silicon boron carbonitride film (SiBCN film), a boroncarbonitride film (BCN film) or the like is formed on the wafer 200. Inthese cases, as the reaction gas, in addition to the O-containing gas,it may be possible to use a C-containing gas such as C₃H₆ or the like,an N-containing gas such as NH₃ or the like, or a B-containing gas suchas BCl₃ or the like.

The present disclosure may be suitably applied to a case where an oxidefilm or a nitride film containing a metal element such as titanium (Ti),zirconium (Zr), hafnium (Hf), tantalum (Ta), niobium (Nb), aluminum(Al), molybdenum (Mo), tungsten (W) or the like, i.e., a metal-basedoxide film or a metal-based nitride film is formed on the wafer 200.That is, the present disclosure may be suitably applied to a case wherea TiO film, a TiN film, a TiOC film, a TiOCN film, a TiON film, a TiBNfilm, a TiBCN film, a ZrO film, a ZrN film, a ZrOC film, a ZrOCN film, aZrON film, a ZrBN film, a ZrBCN film, a HfO film, a HfN film, a HfOCfilm, a HfOCN film, a HfON film, a HfBN film, a HfBCN film, a TaO film,a TaOC film, a TaOCN film, a TaON film, a TaBN film, a TaBCN film, anNbO film, an NbN film, an NbOC film, an NbOCN film, an NbON film, anNbBN film, an NbBCN film, an AlO film, an AlN film, an AlOC film, anAlOCN film, an AlON film, an AlBN film, an AlBCN film, an MoO film, anMoN film, an MoOC film, an MoOCN film, an MoON film, an MoBN film, anMoBCN film, a WO film, a WN film, a WOC film, a WOCN film, a WON film,an MWBN film, a WBCN film or the like is formed on the wafer 200.

In these cases, as the precursor gas, it may be possible to use, forexample, a tetrakis(dimethylamino) titanium (Ti[N(CH₃)₂]₄, abbreviation:TDMAT) gas, a tetrakis(ethylmethylamino) hafnium (Hf[N(C₂H₅) (CH₃)]₄,abbreviation: TEMAH) gas, a tetrakis(ethylmethylamino) zirconium(Zr[N(C₂H₅) (CH₃)]₄, abbreviation: TEMAZ) gas, a trimethylaluminum(Al(CH₃)₃, abbreviation: TMA) gas, a titanium tetrachloride (TiCl₄) gas,a hafnium tetrachloride (HfCl₄) gas or the like. As the reaction gas, itmay be possible to use the aforementioned reaction gas.

That is, the present disclosure may be suitably applied to a case offorming a semimetal-based film containing a semimetal element or ametal-based film containing a metal element. The processing proceduresand processing conditions of these film-forming processes may be thesame processing procedures and processing conditions as those of thefilm-forming process shown in the above-described embodiments andmodifications. Even in these cases, effects similar to those of theabove-described embodiments and modifications may be obtained.

It is preferable that the recipes used for a film-forming process areindividually prepared according to the processing contents and stored inthe memory device 121 c via the electric communication line or theexternal memory device 123. When starting various processes, it ispreferable that the CPU 121 a appropriately selects an appropriaterecipe from the plurality of recipes stored in the memory device 121 caccording to the processing contents. This makes it possible to formthin films of various film types, composition ratios, film qualities andfilm thicknesses for general purposes and with high reproducibility inone substrate processing apparatus. It is also possible to reduce theburden on an operator and to quickly start various processes whileavoiding operation errors.

The above-described recipes are not limited to the case of newlycreating them, but may be prepared by, for example, changing theexisting recipes already installed in the substrate processingapparatus. In the case of changing the recipes, the changed recipes maybe installed in the substrate processing apparatus via an electriccommunication line or a recording medium in which the recipes arerecorded. In addition, by operating the input/output device 122installed in the existing substrate processing apparatus, the existingrecipes already installed in the substrate processing apparatus may bedirectly changed.

As described above, according to the present disclosure, it is possibleto provide a technique capable of uniformly processing a substrate.

The present disclosure provides some embodiments of a technique capableof uniformly processing a substrate.

What is claimed is:
 1. A substrate processing apparatus, comprising: asubstrate support configured to support one or more substrates; aprocess chamber in which the one or more substrates are processed; a gassupplier configured to supply gas; and a plasma generator including: aplurality of first rod-shaped electrodes connected to a high-frequencypower supply; and a second rod-shaped electrode installed between twofirst rod-shaped electrodes among the plurality of first rod-shapedelectrodes, and that is grounded; and a buffer structure configured toaccommodate the plurality of first rod-shaped electrodes and the secondrod-shaped electrode, and having a first wall surface on which a gassupply port that supplies gas into the process chamber is installed,wherein the plasma generator is configured to convert gas into plasma bythe plurality of first rod-shaped electrodes and the second rod-shapedelectrode to supply the plasma-converted gas to the process chamber fromthe gas supply port.
 2. The substrate processing apparatus of claim 1,wherein the second rod-shaped electrode is used in common for the twofirst rod-shaped electrodes among the plurality of first rod-shapedelectrodes.
 3. The substrate processing apparatus of claim 1, whereinthe plurality of first rod-shaped electrodes and the second rod-shapedelectrode are used in a capacitive-coupling manner to convert the gasinto the plasma.
 4. The substrate processing apparatus of claim 1,wherein the substrate support supports a plurality of the substrates atmultiple stages in a vertical direction, and wherein the plurality offirst rod-shaped electrodes and the second rod-shaped electrode arearranged in the vertical direction from a lower portion of the processchamber to an upper portion of the process chamber.
 5. The substrateprocessing apparatus of claim 1, wherein the plurality of firstrod-shaped electrodes and the second rod-shaped electrode are coveredwith electrode protection tubes.
 6. The substrate processing apparatusof claim 1, wherein a number of the plurality of first rod-shapedelectrodes is larger than a number of the second rod-shaped electrode.7. The substrate processing apparatus of claim 1, wherein the plasma isgenerated by applying high-frequency power from the high-frequency powersupply to the plurality of first rod-shaped electrodes.
 8. The substrateprocessing apparatus of claim 1, wherein the buffer structure isinstalled along a stacking direction of the one or more substrates in aregion extending from a lower portion of an inner wall of the processchamber to an upper portion of the inner wall of the process chamber. 9.The substrate processing apparatus of claim 8, wherein the bufferstructure is installed in the process chamber.
 10. The substrateprocessing apparatus of claim 1, wherein the gas supply port is openedto face a center of the process chamber.
 11. The substrate processingapparatus of claim 1, wherein the gas supplier includes: a precursor gassupplier configured to supply a precursor gas into the process chamber;and a reaction gas supplier configured to supply a reaction gas to theplasma generator.
 12. The substrate processing apparatus of claim 11,wherein the reaction gas supplier includes a gas supply hole thatsupplies the reaction gas into the buffer structure, and wherein thebuffer structure has a second wall surface, and the gas supply hole isopened to face the second wall surface of the buffer structure.
 13. Thesubstrate processing apparatus of claim 11, wherein the precursor gassupplier and the buffer structure are installed at positions facing eachother.
 14. The substrate processing apparatus of claim 11, wherein theprecursor gas is a silicon-containing gas, and wherein the reaction gasis a nitrogen-containing gas.
 15. A plasma generating device,comprising: a gas supplier configured to supply gas; a plurality offirst rod-shaped electrodes connected to a high-frequency power supply;a second rod-shaped electrode installed between two first rod-shapedelectrodes among the plurality of first rod-shaped electrodes, and thatis grounded; and a buffer structure configured to accommodate theplurality of first rod-shaped electrodes and the second rod-shapedelectrode, having a first wall surface on which a gas supply port thatsupplies gas into a process chamber is installed, and configured tosupply gas, which has been plasma-converted by the plurality of firstrod-shaped electrodes and the second rod-shaped electrode, to theprocess chamber from the gas supply port.
 16. A reaction tube,comprising: a buffer structure having a first wall surface on which agas supply port that supplies gas into a process chamber is installed,and configured to accommodate, in the buffer structure: a plurality offirst rod-shaped electrodes connected to a high-frequency power supply;and a second rod-shaped electrode installed between two first rod-shapedelectrodes among the plurality of first rod-shaped electrodes, and thatis grounded, wherein in the buffer structure, gas is converted intoplasma by the plurality of first rod-shaped electrodes and the secondrod-shaped electrode.